Title :
A de-cresting technique for polar transmitters using Envelope-Tracking (ET) and SiGe power amplifiers for mobile-WiMAX
Author :
Li, Yan ; Meng, Dongri ; Lopez, Jerry ; Lie, Donald Y C ; Chen, Kevin C J ; Wu, Stanley ; Yang, Tzu-Yin
Author_Institution :
Dept. of Electr. & Comput. Eng., Texas Tech Univ., Lubbock, TX, USA
Abstract :
A decresting algorithm for mobile WiMAX has been developed using time domain clipping and filtering processes for a polar transmitter (TX) using envelope-tracking (ET) and a monolithic SiGe power amplifier (PA). RF/Analog/Digital system and circuits co-design simulations have been performed for mobile WiMAX with 64 QAM OFDM modulation format. It is found that higher power-to-average ratio (PAR) decresting can improve the adjacent channel power ratio (ACPR) and the overall TX system efficiency, but at the cost of its EVM degradation. Our system simulations show that careful design of signal decresting can improve the overall polar TX system efficiency from 28.1% to 30.3% while the TX output can still meet the stringent WiMAX TX mask and EVM specs.
Keywords :
Ge-Si alloys; OFDM modulation; WiMax; mobile radio; monolithic integrated circuits; power amplifiers; quadrature amplitude modulation; radio transmitters; radiofrequency integrated circuits; 64 QAM OFDM modulation format; SiGe; adjacent channel power ratio; circuits codesign simulations; envelope tracking; filtering process; mobile WiMAX; monolithic SiGe power amplifier; polar transmitters; power-to-average ratio; signal decresting technique; time domain clipping process; Circuit simulation; Digital systems; Filtering algorithms; Germanium silicon alloys; Power amplifiers; Radio frequency; Radiofrequency amplifiers; Silicon germanium; Transmitters; WiMAX; Envelope-Tracking (ET); PAR; Polar transmitter; Power Amplifier (PA); clipping ratio (CR); decresting; mobile WiMAX;
Conference_Titel :
Microwaves, Communications, Antennas and Electronics Systems, 2009. COMCAS 2009. IEEE International Conference on
Conference_Location :
Tel Aviv
Print_ISBN :
978-1-4244-3985-0
DOI :
10.1109/COMCAS.2009.5386015
